[Modern possibilities for transcatheter pulmonary valve replacement]. / Sovremennye vozmozhnosti transkateternogo protezirovaniya klapana legochnoi arterii.

The literature review is devoted to transcatheter pulmonary valve replacement. The authors summarize the indications, clinical data and current capabilities of transcatheter pulmonary valve replacement. The authors also overviewed modern valves for transcatheter pulmonary artery replacement. Effectiveness of transcatheter pulmonary valve implantation has been substantiated. Various studies comparing the outcomes of different valve systems for endovascular implantation were analyzed. The authors concluded the prospects for transcatheter pulmonary valve implantation.

[Robot-assisted atrial septal defect closure in adults: first experience in Russia]. / Robot-assistirovannoe zakrytie defekta mezhpredserdnoi peregorodki u vzroslykh: pervyi opyt v Rossii.

AIM: To analyze immediate results of minimally invasive robot-assisted atrial septal defect (ASD) closure in adults. MATERIAL AND METHODS: For the period from March 2012 to November 2016 sixty patients with contraindications to endovascular procedure have undergone robot-assisted atrial septal defect closure at Meshalkin Siberian Federal Biomedical Research Center. Mean age was 34.5±11.3 years, body mass index - 24.6±4.0 kg/m2. 48 (80%) patients had NYHA class II before surgery. In 37 (61.7%) patients isolated ASD with deficiency or absence of one edge was diagnosed, isolated ASD with primary septum aneurysm - in 16 (26.7%) cases, 7 (11.6%) patients had reticulate ASD. 5 (8.3%) patients had concomitant tricuspid valve insufficiency required surgical repair (suture annuloplasty). All operations were performed under cardiopulmonary bypass with peripheral cannulation. Right-sided anterolateral mini-thoracotomy was used in the first 43 patients. Following 17 patients underwent completely endoscopic procedure. Depending on the shape, size and anatomical features of the defect we performed suturing (14 patients, 23.3%) or repair with xenopericardial patch (46%, 76.6%). RESULTS: Mean CPB and aortic cross-clamping time was 89.1±28.7 and 24.8±9.5 min, respectively. Postoperative variables: mechanical ventilation 3.3±1.5 hours, ICU-stay - 18.2±3.7 hours, postoperative hospital-stay - 13.4±5.7 days. There were no mortality and any life-threatening intra- and postoperative complications. Cases of conversion to thoraco-/sternotomy and postoperative bleeding followed by redo surgery were also absent. 23 patients were followed-up within 1 year, 6 patients - within 2 years, 3 patients - within 3 years. All patients were in NYHA class I-II with 100% freedom from ASD recanalization and redo surgery. According to echocardiography data there were decreased right heart, pulmonary artery pressure and preserved left ventricular function in early postoperative period and 1 year after surgery. CONCLUSION: In view of favorable course of postoperative period, no significant specific complications and encouraging immediate results we can talk about endoscopic robot-assisted ASD closure in adults as a safe and effective alternative to surgical treatment.

The Neutrons for Science Facility at SPIRAL-2.

The neutrons for science (NFS) facility is a component of SPIRAL-2, the new superconducting linear accelerator built at GANIL in Caen (France). The proton and deuteron beams delivered by the accelerator will allow producing intense neutron fields in the 100 keV-40 MeV energy range. Continuous and quasi-mono-kinetic energy spectra, respectively, will be available at NFS, produced by the interaction of a deuteron beam on a thick Be converter and by the 7Li(p,n) reaction on thin converter. The pulsed neutron beam, with a flux up to two orders of magnitude higher than those of other existing time-of-flight facilities, will open new opportunities of experiments in fundamental research as well as in nuclear data measurements. In addition to the neutron beam, irradiation stations for neutron-, proton- and deuteron-induced reactions will be available for cross-sections measurements and for the irradiation of electronic devices or biological cells. NFS, whose first experiment is foreseen in 2018, will be a very powerful tool for physics, fundamental research as well as applications like the transmutation of nuclear waste, design of future fission and fusion reactors, nuclear medicine or test and development of new detectors.

Outcomes of the Ross procedure in patients with an accompanying ascending aortic aneurysm.

Analysed in the article are the results of the Ross procedure in patients presenting with dilatation of the ascending portion of the aorta. A combination of aortic valve defects with dilatation of the ascending aorta of more than 45 mm supposes simultaneous prosthetic repair of the aortic valve and ascending aorta. The most common surgical procedure remains the Bentall-DeBono operation whose main disadvantage is associated with implantation of a mechanical prosthesis and the necessity of lifelong anticoagulant therapy. An alternative method is the Ross procedure demonstrating low risk of thromboembolic complications and freedom from anticoagulant therapy. Over the period from 2002 to April 2015, specialists of the Novosibirsk Scientific Research Institute of Circulatory Pathology named after Academician E.N. Meshalkin carried out a total of 162 Ross procedures in patients presenting with accompanying dilatation of the ascending aorta (more than 45 mm). The mean diameter of the aorta at the level of Valsalva sinuses amounted to 45.6±8.6 mm, with that of the ascending aortic portion equalling 53.4±7.8 mm. The technique of total replacement of the aortic root was used in all cases. When the aneurysm extended to distal portions of the ascending aorta, additionally performed were the following procedures: in 24 patients--reduction aortoplasty, in 6 patients--replacement of the resected aorta with an insert from xenopericardium, and in 2 patients with a vascular graft. The average duration of follow up amounted to 40.1±21.6 months. Ten patients were subjected to repeat operations for autograft dysfunction. There were no reoperations on the ascending portion of the aorta. The regression analysis revealed that predictors of the development of autograft dysfunction were the baseline dilatation of the fibrous ring (FR) of the aortic valve of more than 27 mm (p=0.04) and uncorrected arterial hypertension in the postoperative period (p=0.03). In the group of patients with the FR less than 27 mm there were no cases of allograft dysfunction. The results of the study suggest that the Ross procedure is a safe and effective method in patients with accompanying dilatation of the ascending aorta. Risk factors for autograft dysfunction are dilatation of the FR of the aortic valve exceeding 27 mm and arterial hypertension in the postoperative period.

Light charged-particle production in 96 MeV neutron-induced reactions on carbon and oxygen.

In recent years, an increasing number of applications involving fast neutrons have been developed or are under consideration, e.g. radiation treatment of cancer, neutron dosimetry at commercial aircraft altitudes, soft-error effects in computer memories, accelerator-driven transmutation of nuclear waste and energy production and determination of the response of neutron detectors. Data on light-ion production in light nuclei such as carbon, nitrogen and oxygen are particularly important in calculations of dose distributions in human tissue for radiation therapy at neutron beams, and for dosimetry of high-energy neutrons produced by high-energy cosmic radiation interacting with nuclei (nitrogen and oxygen) in the atmosphere. When studying neutron dose effects, it is especially important to consider carbon and oxygen, since they are, by weight, the most abundant elements in human tissue. Preliminary experimental double-differential cross sections of inclusive light-ion (p, d, t, (3)He and alpha) production in carbon induced by 96-MeV neutrons have been presented. Energy spectra were measured at eight laboratory angles: 20, 40, 60, 80, 100, 120, 140 and 160 degrees. Measurements were performed at The Svedberg Laboratory (TSL), Uppsala, using the dedicated MEDLEY experimental setup. The authors have earlier reported experimental double-differential cross sections of inclusive light-ion production in oxygen. In this paper, the deduced kerma coefficients for oxygen has been presented and compared with reaction model calculations.

The TSL neutron beam facility.

A new quasi-monoenergetic neutron beam facility has been constructed at The Svedberg Laboratory (TSL) in Uppsala, Sweden. Key features include a neutron energy range of 11-175 MeV, high fluxes, user flux control, flexible neutron field size and shape, and spacious and easily accessible user area. The first results of the beam characterisation measurements are reported.

Elastic neutron scattering studies at 96 MeV for transmutation.

Elastic neutron scattering from (12)C, (14)N, (16)O, (28)Si, (40)Ca, (56)Fe, (89)Y and (208)Pb has been studied at 96 MeV in the10-70 degrees interval, using the SCANDAL (SCAttered Nucleon Detection AssembLy) facility. The results for (12)C and (208)Pb have recently been published, while the data on the other nuclei are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. A novel method for normalisation of the absolute scale of the cross section has been used. The estimated normalisation uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. Elastic neutron scattering is of utmost importance for a vast number of applications. Besides its fundamental importance as a laboratory for tests of isospin dependence in the nucleon-nucleon, and nucleon-nucleus, interaction, knowledge of the optical potentials derived from elastic scattering come into play in virtually every application where a detailed understanding of nuclear processes is important. Applications for these measurements are dose effects due to fast neutrons, including fast neutron therapy, as well as nuclear waste incineration and single event upsets in electronics. The results at light nuclei of medical relevance ((12)C, (14)N and (16)O) are presented separately. In the present contribution, results on the heavier nuclei are presented, among which several are of relevance to shielding of fast neutrons.